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Pregnancy Toxaemia In Ewes

With cold, wintry weather and low or non-existent paddock feed in many areas, ewes nearing lambing may be at risk of developing pregnancy toxaemia.

By Department of Primary Industries - 12th July 2006 - Back to News

Pregnancy toxaemia, also known as twin lamb disease or ketosis, affects ewes in late pregnancy ‑ especially those bearing twins.

The disease is caused by poor nutrition during the last 6 weeks of pregnancy.

Ewes should have a body condition score at lambing of about 3 on a scale of 1 to 5, where a score of 1 is a very low condition score and 5 is very fat.

During the final month of pregnancy the nutritional requirements of pregnant ewes increase to 1.5 times their maintenance requirement and to 2.5 maintenance after lambing.

Cold weather further increases energy demands.

Fat ewes on poor-quality feed are particularly susceptible, as they often can't eat enough to meet their basic nutritional requirement, even though plenty of feed may be available.

More often there is little pasture feed available and insufficient supplementary feed is provided during that period.

As a guide, a 45 kg ewe needs 450 grams of cereal per day to maintain its weight if no other feed is available. A heavier ewe would require proportionally more. Limited pasture may provide some of the nutrition and so the amount of grain can be reduced accordingly.

Ewes affected with pregnancy toxaemia may stand apart from the mob, refuse to travel, appear dull and disinterested in their surroundings and are blind and stargaze. They eventually become unable to stand and lie down, convulse and die.

Treatment is rarely successful unless commenced immediately symptoms are noticed.

Treatment consists of 100-120mls (4 ounces) of glycerine as a drench at least twice daily. Propylene glycol can be substituted for glycerine.

Pregnancy toxaemia can be prevented with good management, namely, attention to nutrition and avoiding over-fat ewes in late pregnancy.

It should be remembered though that not every 'downer' ewe has pregnancy toxaemia. Other causes of ewes going down may include hypocalcaemia (lack of available calcium), and hypomagnesaemia (a lack of magnesium), septicaemia, anaemia, or predation. Pregnancy toxaemia only occurs prior to lambing, whereas hypocalcaemia can occur either before or after lambing.

Scanning (ultrasound) ewes to determine pregnancy status, ie empty, singles or twins, is a very useful management tool to allow drafting of sheep into different classes for selective feeding of single and twin‑bearing ewes.

Further information is available from DPI Animal Health staff or from your veterinary adviser.

Source: http://gippsland.com/

Published by: news@gippsland.com